What is the limit for photoautotrophic plankton growth rates?
What is the limit for photoautotrophic plankton growth rates?
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DOI：
10.1093/plankt/fbw067
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发表时间：
2017-01-01
影响因子：
2.1
通讯作者：
Raven, John A.
中科院分区：
文献类型：
--
作者：
Flynn, Kevin J.;Raven, John A.
了解光合初级生产者潜在的最大光合自养生长速率是我们理解营养和光合地球化学过程的基础，在应用藻类学中具有重要意义。当考虑在自然光：暗循环下的日整合C特异性生长时，合理的RuBisCO活性（K-cat与细胞RuBisCO含量结合）将生长限制在每天不到几倍。长时间的C-特定的增长率高于约。1.3 d（-1）因此显得越来越不可信。之间的差异RuBisCO-加盖率和报告的微藻特定的生长速率，包括温度-生长速率的关系，可以解释的转化错误的生长速率测定参考细胞计数或最常见的叶绿素，或从短期测量外推。需要对酶活性和每日C特异性生长速率进行耦合研究，以提供高生长速率的明确证据。然而，似乎很可能，进化具有高Kcat（对于CO2，Km可能伴随增加）的RuBisCO的选择压力将是低的，因为其他因素，例如光限制（由于自遮蔽而在生物量生长期间发展）、营养限制、CO2消耗和pH升高，都将迅速抑制实现的比生长速率。
Knowing the potential maximum photoautotrophic growth rate for planktonic primary producers is fundamental to our understanding of trophic and biogeochemical processes, and of importance in applied phycology. When day-integrated C-specific growth is considered over natural light: dark cycles, plausible RuBisCO activity (K-cat coupled with cellular RuBisCO content) caps growth to less than a few doubling per day. Prolonged periods of C-specific growth rates above ca. 1.3 d(-1) thus appear increasingly implausible. Discrepancies between RuBisCO-capped rates and reported microalgal-specific growth rates, including temperature-growth rate relationships, may be explained by transformational errors in growth rate determinations made by reference to cell counts or most often chlorophyll, or by extrapolations from short-term measurements. Coupled studies of enzyme activity and day-on-day C-specific growth rates are required to provide definitive evidence of high growth rates. It seems likely, however, that selective pressure to evolve a RuBisCO with a high Kcat (with a likely concomitant increase in Km for CO2) would be low, as other factors such as light limitation (developing during biomass growth due to self-shading), nutrient limitations, CO2 depletion and pH elevation, would all rapidly depress realized specific growth rates.